(Ah, Willisville; I was there just one month ago. I was working a short stint in Little Current. In July, I hiked from the highway up onto the hill overlooking the lake. I suppose you call it God's country.... with reason. I should get up that way again around the end of March).
All of the manual focus Mamiya 645 lenses will fit all of the cameras. Just that they will not give meter coupling (or AF) on the newer AF cameras. The AF lenses may not fit the older MF bodies. That was as of a couple years ago, so something may have changed with the newer AF camera bodies.